177x Filetype PPT File size 1.03 MB Source: www.ems.psu.edu
Polymers Polymers (see Roe: Methods of X-ray and Neutron Scattering in Polymer Science (2000)) (see Roe: Methods of X-ray and Neutron Scattering in Polymer Science (2000)) semicrystalline poly(3-hydroxybuyrate) semicrystalline poly(3-hydroxybuyrate) note amorphous scattering region note amorphous scattering region Polymers Polymers (see Roe: Methods of X-ray and Neutron Scattering in Polymer Science (2000)) (see Roe: Methods of X-ray and Neutron Scattering in Polymer Science (2000)) Degree of crystallinity Degree of crystallinity Pattern consists of relatively sharp crystalline peaks + Pattern consists of relatively sharp crystalline peaks + amorphous scattering amorphous scattering Comparing intensities of the two ––> % crystallinity Comparing intensities of the two ––> % crystallinity Polymers Polymers (see Roe: Methods of X-ray and Neutron Scattering in Polymer Science (2000)) (see Roe: Methods of X-ray and Neutron Scattering in Polymer Science (2000)) Degree of crystallinity Degree of crystallinity Pattern consists of relatively sharp crystalline peaks + Pattern consists of relatively sharp crystalline peaks + amorphous scattering amorphous scattering Comparing intensities of the two ––> % crystallinity Comparing intensities of the two ––> % crystallinity Problems: Problems: small crystallite size broadens peaks small crystallite size broadens peaks extensive amounts of crystal imperfections extensive amounts of crystal imperfections thermal motion thermal motion Polymers Polymers (see Roe: Methods of X-ray and Neutron Scattering in Polymer Science (2000)) (see Roe: Methods of X-ray and Neutron Scattering in Polymer Science (2000)) Degree of crystallinity Degree of crystallinity Pattern consists of relatively sharp crystalline peaks + Pattern consists of relatively sharp crystalline peaks + amorphous scattering amorphous scattering Comparing intensities of the two ––> % crystallinity Comparing intensities of the two ––> % crystallinity Methods for separation: Methods for separation: guess guess measure 100% amorphous specimen measure 100% amorphous specimen Polymers Polymers (see Roe: Methods of X-ray and Neutron Scattering in Polymer Science (2000)) (see Roe: Methods of X-ray and Neutron Scattering in Polymer Science (2000)) Total scattering by amorphous & crystalline phases Total scattering by amorphous & crystalline phases Q is called the invariant s = diffraction vector Q is called the invariant s = diffraction vector
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